1. Field of the Invention
The present invention relates to animal feed additives.
2. Description of the Related Art
A variety of animal feed additives have conventionally been proposed. For example, known are a meet-quality improving feed (Japanese Patent Application Laid-Open (Kokai) No. 61-119144) which comprises, as an essential component, the powder, extract and/or fermentation product of at least one plant selected from ginseng, watermelon, loofah, sweet tea vine (Jiaogulan), cucumber, melon, licorice, soybean, hare""s ear root (Bupleurum falcatum), a(d)zuki bean and tea leaves; a feed additive for improving smell of animal meat (Japanese Patent Application Laid-Open (Kokai) No. 5-276878) which comprises one or more than one of black pepper, clove, ginger, garlic and onion, and essential oils thereof; a method for improving meat quality (Japanese Patent Application Laid-Open (Kokai) No. 6-209720) which comprises mixing a material containing tannin, caffeine, etc., with a conventional feed and supplying domestic animals with the resulting mixed feed; and a feed (Japanese Patent Application Laid-Open (Kokai) No. 2000-139360) comprising mannan and a mannan degrading enzyme.
Each of these related arts is however developed for limited uses.
The present inventors have therefore carried out various investigations on a general-purpose animal feed additive usable for multiple purpose applications. As a result, they have completed the present invention.
The present invention relates to an animal feed additive, which comprises at least two components selected from the group consisting of the following components (a), (b) and (c):
(a) at least one herb selected from Pine Needle, Hawthorn Fruit, Bighead Atractylodes Rhizome, Milkvetch Root, Skullcap Root, Tangerine Fruit and Mint siftings;
(b) a live bacteria mixture composed of a yeast cell wall and a live bacteria preparation containing Lactobacillus acidophilus and/or Enterococcus faecium; and
(c) an organic acid.
The animal feed additive according to the present invention brings about a variety of effects such as improvement in the smell of animal meat, imparting of an animal with disease resistance, antibacterial action, immunoactivation, hormone regulation, antioxidant action, suppression of proliferation of microorganisms, regulation of the stomach, regulation of metabolism and improvement of appetite.
The herbs to be added as the component (a) to the animal feed additive of the present invention can be used as are or if necessary, after ground down or in the form of an essential oil. These herbs may be used either singly or in combination according to the using purpose. When at least two herbs are employed, they are usually mixed at an equal ratio, but their amounts can be adjusted as needed according to uses.
The live bacterial mixture to be added to the animal feed additive of the present invention as the component (b) contains a yeast cell wall and Lactobacillus acidophilus and/or Enterococcus faecium. 
The yeast cell wall to be used in the present invention can be fractionated from various yeast cells in a conventional manner. It usually contains, in addition, yeast and/yeast fermentation product. Examples of the yeast usable here include Saccharomyces spp. strains such as Saccharomyces cerevisiae, Saccharomyces uvarum, Saccharomyces diastaticus and Saccharomyces rouxii; Schizosaccharomyces spp. strains such as Schizosaccharomyces pombe; Saccharomycodes spp. strains such as Saccharomycodes ludwigii; Hanseniaspora spp. strains such as Hanseniaspora valbyensis; Kluyveromyces spp. strains such as Kluyveromyces fragilis and Kluyveromyces lactis; Pichia spp. strains such as Pichia membranaefaciens; Hansenula spp. strains such as Hansenula anomala; Debaryomyces spp. strains such as Debaryomyces hansenii; Lipomyces spp. strains such as Lipomyces starkeyi; Brettanomyces spp. strains such as Brettanomyces bruxellensis; and Candida spp. strains such as Candida utilis, Candida tropicalis and Candida lipolytica. 
The live-bacteria mixture of the present invention can be prepared by mixing a live bacteria preparation composed of Lactobacillus acidophilus and/or Enterococcus faecium with a yeast cell wall. Lactobacillus acidophilus and Enterococcus faecium are each preferably microencapsulated for heightening stability upon storage and availability in vivo.
Lactobacillus acidophilus and Enterococcus faecium can be microencapsulated separately as described above. Alternatively, their mixture prepared in advance may be microencapsulated.
In the live bacteria mixture of the present invention, Lactobacillus acidophilus and/or Enterococcus faecium may be added in an amount of 1xc3x97105 to 1xc3x971012 CFU/g, preferably 1xc3x97108 to 1xc3x971010 CFU/g relative to 1 g of a yeast cell wall.
As the organic acid to be added as the component (c) to the animal feed additive of the present invention, various organic acids may be used. Examples include citric acid, malic acid, fumaric acid, formic acid, propionic acid, lactic acid and tartaric acid. Of these, citric acid, fumaric acid, formic acid and lactic acid are preferred.
The animal feed additive of the present invention contains at least two components selected from the group consisting of the components (a), (b) and (c). In other words, it contains a combination of components (a) and (b), components (a) and (c), components (b) and (c) or components (a), (b) and (c).
The animal feed additive of the present invention contains 30 to 70 wt. % of the herb (a), 20 to 50 wt. % of the live bacteria mixture (b), and 10 to 50 wt. % of the organic acid (c), of which the animal feed additive containing 40 to 60 wt. % of (a), 30 to 40 wt. % of (b) and 15 to 40 wt. % of (c) is particularly preferred.
The animal feed additive of the present invention can be fed to animals as is, but in general, feeding of it as a feed mixture is preferred. Although the mixing ratio of this animal feed additive differs depending on the kind of animals to be fed or feeding purpose, addition of 0.0001 to 3 wt. % to feed is usually preferred.
Animals to be fed with the animal feed additive of the present invention are, for example, swine, fowl and cattle.
The animal feed additive of the present invention is more effective when used in combination with an antibacterial agent such as oxytetracycline, morantel citrate, efrotomycin or colistin sulfate.